Ivan Lendl has revealed that family concerns were behind his shock decision to quit as Andy Murray's coach earlier this year.

Speaking candidly for the first time since he resigned as the British No.1's mentor, Lendl said that the time needed to inspire former Wimbledon champion Murray to further Grand Slam glory was something he could no longer offer with new family issues to consider.

Murray tipped to regain top-four spot

Andy Murray will return to the world's top four by next year, according to his former coach Brad Gilbert.

Murray, who has not won a title in 13 months, has dropped to ninth in the world rankings since returning from back surgery earlier this year. But Gilbert, who coached Murray for 16 months from July 2006, has tipped him to rediscover his best form very soon.

"I'm sure Andy would be the first to tell you that he's had a disappointing year and he hasn't come back as quickly from the back surgery as he would like," Gilbert said. "Albeit, he's 27, I expect soon he will turn around what's happened.

"I think more than anything, since Wimbledon last year he's really struggled against top-10 opponents. Besides the injury, he changed coaches, with Lendl leaving after Miami, now bringing on Mauresmo.

"I think more than anything he works unbelievably hard. As long as he has his health, at some point he's going to figure out how to turn around his recent losses versus the top 10. Once he does that, I expect for sure by 2015 that he will be back in the top four in the world."

"Just doing 20 weeks a year was hard," Lendl revealed as he met with Murray and his new team in Flushing Meadows ahead of the US Open. "Andy, after his back surgery and winning Wimbledon [in 2013], needed more time not less.

"Everyone is different, and when you win a big tournament like Wimbledon, it's not easy sometimes. Some people find it more difficult than others, and I'm glad Andy found Amelie [Mauresmo] who can give him the time he needs.

"I need to go to Prague more often now to see my mother, who was 79 this month. And my youngest daughter has also returned home; she is 16 and had been staying with horse people, because she does a lot of horse-riding, but now she is living with us again.

"In the end Andy and I sat down and I said: 'Look, if you can come up with a way how it can work please let me know', but neither one of us could figure out how to do that."

Lendl's departure left Murray still searching for a new coach going into this year's French Open, with the Briton eventually plumping for Mauresmo in time for the grass-court season. But while Murray is yet to make a Grand Slam final since his 2013 Wimbledon victory, Lendl has tipped him for further glory.

"Andy's a great player," Lendl said. "He is fully capable of winning more majors. As for how the coaching situation works out, we don't know yet. But I do know that the person who knows Andy the best is Dani [Vallverdu, Murray's assistant coach].

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"You guys don't understand how much I relied on Dani, and I hope Amelie relies on Dani as well. Many times he would come to me and say: 'Hey, you need to stop the practice'. And I would say: 'What? Andy looks fine to me'. And Dani would say: 'No, he's done'. And two or three minutes later, he was done. So you get that two or three times and you start listening much better."

Despite his split from Murray, Lendl has not ruled out a return to coaching in the future, although he insisted the player would have to be right for him.

"People ask me if I'm going to coach again," Lendl said. "Maybe eventually but it has to fit right. It wouldn't have worked if Andy had called me two years earlier, or if he had called me two years later. And it has to be someone I feel I can offer something to. If it was John Isner, for example, I am not going to be able to tell him how to hit a serve."